1. Field of the Invention
The present invention relates to the field of tennis ball handling equipment, and in particular, to apparatus for retrieving and transporting tennis balls.
2. Prior Art
In the past few years, the popularity of tennis as a recreational sport has increased tremendously. The number of tennis players in the United States alone has been estimated to be in excess of 20 million, and more and more people take up the sport each year. Both neophyte and experienced players alike desire to improve and maintain their tennis skills by practice and drill exercises. One excellent and relatively convenient way for a player to get the needed practice is to utilize a ball throwing machine, thereby eliminating the requirement for a second player or even a regulation size tennis court, as the machines typically are set up in special lanes or practice alleys in which a player practices returning balls propelled by the ball machine. Since the ball throwing machines propel balls in rapid succession, a large number of balls are needed to feed the machine in order to keep the machine in operation. Even if the ball thrower is constructed with a large capacity ball hopper, a large number of balls is required to avoid very frequent interruptions of practice to pick up the spent balls and reload the ball hopper, which in turn results in having many loose balls lying on the court, distracting the player and providing possible sources of injury if the player steps on or trips over a loose ball.
To avoid these disadvantages and meet the ball requirements for these automatic machines, ball retrieval machines have been developed to retrieve balls previously thrown and to transport them to the intake of the ball throwing machine. One such type of machine uses an air pressure source to propel balls through a tube from a collection point, such as at the bottom of a slope or incline constructed in the playing surface, to the intake of the ball throwing machine. This type of ball retriever suffers the disadvantage that if one ball is not propelled with sufficient velocity to be carried through the tube to the feed of the ball thrower, and therefore lodges somewhere in the tube, the next ball will likewise stop in the tube, and a ball jam results. In a typical application of this type of machine, very high reliability is required, since it is very undesirable, particularly for commercial uses, to intermittently shut down the ball thrower to remedy a ball jam in the ball retriever mechanism.
Another type of ball transport utilizes a conveyor mechanism to lift the spent balls to the feed of the ball thrower, the conveyor having flights of buckets mounted on motor driven endless belts or chains. The balls are scooped into buckets at ground level and are lifted to the ball hopper of the throwing machine, where the bucket is inverted by the movement around a sprocket, thereby dumping the balls into the ball hopper. This type of ball transport is typically very reliable, but is very expensive to manufacture and install, and is a relatively permanent fixture.